Oil filter



FIG. 1 is a perspective view of an oil filter, showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof; and,

FIG. 4 is a front elevational view thereof; the rear elevational view,left-side elevational view, and right-side elevational view all beingmirror images thereof.

I claim the ornamental design for a oil filter, as shown and described.